US8158022B2 - Polarizing film - Google Patents

Polarizing film Download PDF

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Publication number
US8158022B2
US8158022B2 US12/981,684 US98168410A US8158022B2 US 8158022 B2 US8158022 B2 US 8158022B2 US 98168410 A US98168410 A US 98168410A US 8158022 B2 US8158022 B2 US 8158022B2
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US
United States
Prior art keywords
polarizing film
azo compound
film according
carbon atoms
group
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Expired - Fee Related
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US12/981,684
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English (en)
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US20110163268A1 (en
Inventor
Hisanari Onouchi
Sadahiro Nakanishi
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Nitto Denko Corp
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Nitto Denko Corp
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Assigned to NITTO DENKO COROPORATION reassignment NITTO DENKO COROPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NAKANISHI, SADAHIRO, ONOUCHI, HISANARI
Publication of US20110163268A1 publication Critical patent/US20110163268A1/en
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Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/20Filters
    • G02B5/22Absorbing filters
    • G02B5/223Absorbing filters containing organic substances, e.g. dyes, inks or pigments
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18Manufacture of films or sheets
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09BORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B29/00Monoazo dyes prepared by diazotising and coupling
    • C09B29/06Monoazo dyes prepared by diazotising and coupling from coupling components containing amino as the only directing group
    • C09B29/095Amino naphthalenes
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00Liquid crystal materials
    • C09K19/52Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • C09K19/60Pleochroic dyes
    • C09K19/601Azoic
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2323/00Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
    • C09K2323/03Viewing layer characterised by chemical composition
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2323/00Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
    • C09K2323/03Viewing layer characterised by chemical composition
    • C09K2323/031Polarizer or dye

Definitions

  • the present invention relates to a polarizing film showing a high dichroic ratio on a short wavelength side of visible light.
  • an azo compound (dichroic dye) showing absorption dichroism in a short wavelength region (380 to 500 nm) of visible light.
  • a neutral gray polarizing film polarizing film having averaged transmittance and averaged polarization degree in a wide visible light region of 380 to 780 nm
  • a dye showing absorption dichroism in a long wavelength region more than 500 nm to 780 nm
  • the azo compound described in the above-mentioned JP-A-2008-133421 shows a relatively high dichroic ratio on the short wavelength side (380 to 500 nm) of visible light, the dichroic ratio thereof is at most about 30, and 50 or less. Thus, the dichroic ratio thereof is still low under the present situation.
  • the present inventors have newly synthesized an azo compound having a benzene ring and two naphthalene rings in its molecular structure, in which one of the naphthalene rings is linked to the benzene ring by an amide bond, based on a presumption that an azo compound having a structure that includes an aromatic ring having high planarity and has a properly short molecular major axis is suitable.
  • a polarizing film having a high dichroic ratio in a short wavelength region of visible light is obtained.
  • the invention has been made in order to solve the above-mentioned conventional problem, and an object thereof is to provide a polarizing film having a high dichroic ratio in a short wavelength region of visible light.
  • the present invention provides the followings.
  • a polarizing film comprising an azo compound represented by the following formula (1):
  • X is a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and M is a counter ion.
  • the polarizing film according to item 1 or 2 which has a thickness of 0.1 to 40 ⁇ m.
  • the polarizing film contains an azo compound represented by the formula (1), and such a compound can form a molecular structure having high planarity by including a benzene ring and two naphthalene rings in its molecular structure and linking one of the naphthalene rings to the benzene ring by an amide bond.
  • a ⁇ - ⁇ interaction between the molecules becomes strong, resulting in mutual stacking of the benzene rings and mutual stacking of the naphthalene rings, whereby a polarizing film having a high dichroic ratio can be obtained.
  • the conjugation length thereof becomes short as compared to a case where the respective aromatic rings (the benzene ring and the naphthalene rings are linked only by azo bonds), so that the polarizing film shows maximum absorption in a short wavelength region of visible light.
  • the amount of the azo compound contained in the polarizing film is 30 to 100% by weight based on the total weight of the polarizing film.
  • the polarizing film has a thickness of 0.1 to 40 ⁇ m.
  • the polarizing film shows dichroism in a wavelength region of 380 to 500 nm in visible light.
  • the polarizing film has a dichroic ratio of 55 or more.
  • the polarizing film according to this embodiment contains a specific azo compound described later.
  • the azo compound is contained in the polarizing film preferably in an amount of 30 to 100% by weight, based on the total weight of the polarizing film.
  • the polarizing film preferably has a thickness of 0.1 to 40 ⁇ m.
  • the polarizing film preferably shows absorption dichroism in a short wavelength region (380 to 500 nm) of visible light. Such a characteristic is obtained by orientation of the azo compound in the polarizing film.
  • the polarizing film preferably has a dichroic ratio of 55 or more.
  • the azo compound used in the polarizing film according to this embodiment is a compound represented by the following formula (1), and more preferably a compound represented by the following formula (2):
  • X is a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and preferably a cyano group.
  • M is a counter ion, preferably an alkali metal ion, and especially preferably selected from Li + , Na + and K + .
  • the above-mentioned azo compound has a property of causing an isotropic phase-liquid crystal phase transition (lyotropic liquid crystallinity) when the azo compound is dissolved in a solvent to form a solution and the temperature or the concentration of the solution is changed, and is highly oriented by orientation regulating force such as shear stress. Accordingly, a polarizing film showing a high dichroic ratio can be obtained.
  • Synthesis methods of the above-mentioned azo compound include, for example, a method of converting a 6-amino naphthalenedisulfonic acid derivative to a diazonium salt by using sodium nitrite and hydrochloric acid, allowing the resulting diazonium salt to conduct a coupling reaction with 2-amino naphthalenesulfonic acid in an acidic cool-temperature aqueous solution to obtain a monoazo compound, and then, reacting the resulting monoazo compound with an acid chloride in the presence of pyridine in a nonpolar solvent such as N-methylpyrrolidone.
  • a nonpolar solvent such as N-methylpyrrolidone
  • the polarizing film having a thickness of less than 10 ⁇ m can be obtained by dissolving the above-mentioned azo compound in a solvent and applying the resulting solution onto an orientation substrate in a thin film form.
  • the solvent is one which can dissolve the azo compound, and preferably a hydrophilic solvent.
  • a hydrophilic solvent include water, alcohols, cellosolves or mixed solvents thereof.
  • orientation substrate examples include a drawn film or a rubbing-treated polymer film. After formation of the polarizing film on a surface of the orientation substrate, the polarizing film may be removed by peeling or used as it is.
  • the above-mentioned application method there can be used, for example, a bar coater, a slot die coater or the like.
  • the polarizing film having a thickness exceeding 10 ⁇ m can be obtained, for example, by immersing a polyvinyl alcohol film in an aqueous solution containing the above-mentioned azo compound, followed by drawing the same.
  • the aqueous solution preferably contains the above-mentioned azo compound in an amount of 0.5 to 30% by weight, based on the total weight of the aqueous solution.
  • the thickness of the above-mentioned polyvinyl alcohol film before drawing is preferably from 15 to 100 ⁇ m.
  • the total draw ratio of the polyvinyl alcohol film is, for example, from twice to 6 times the original length thereof.
  • the polarizing film produced as described above is suitably used in various panels attached, for example, to computers, cellular phones, television sets and the like.
  • 6-Amino-1,3-naphthalenedisulfonic acid was converted to a diazonium salt by using sodium nitrite and hydrochloric acid, and a coupling reaction of the diazonium salt with 5-amino-2-naphthalenesulfonic acid was conducted in an acidic cool-temperature aqueous solution to obtain a monoazo compound. Then, a coupling reaction of this monoazo compound with 4-cyanobenzoyl chloride was conducted in N-methylpyrrolidone to convert the sulfonic acid salt to a lithium salt, thereby obtaining an azo compound represented by the following formula (3) (a lyotropic liquid crystal showing a nematic liquid crystal phase in an aqueous solution).
  • the above-mentioned azo compound was dissolved in ion-exchanged water, and the concentration thereof was adjusted to 5% by weight to prepare a coating solution.
  • This coating solution was applied onto a rubbing-treated and corona-treated cycloolefin polymer film (manufactured by Zeon Corporation, trade name: “ZEONOR”, thickness: 50 ⁇ m) by using a bar coater, followed by air drying to obtain a polarizing film having a thickness of 0.4 ⁇ m.
  • This polarizing film had a maximum absorption wavelength of 405 nm and a dichroic ratio of 59.
  • V-7100 ultraviolet-visible spectrophotometer
  • k 1 represents the transmittance of linearly-polarized light in a maximum transmittance direction
  • k 2 represents the transmittance of linearly-polarized light in a direction perpendicular to the maximum transmittance direction.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Medicinal Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Polarising Elements (AREA)
US12/981,684 2010-01-05 2010-12-30 Polarizing film Expired - Fee Related US8158022B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010-000654 2010-01-05
JP2010000654A JP5351060B2 (ja) 2010-01-05 2010-01-05 偏光膜

Publications (2)

Publication Number Publication Date
US20110163268A1 US20110163268A1 (en) 2011-07-07
US8158022B2 true US8158022B2 (en) 2012-04-17

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US12/981,684 Expired - Fee Related US8158022B2 (en) 2010-01-05 2010-12-30 Polarizing film

Country Status (5)

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US (1) US8158022B2 (ja)
JP (1) JP5351060B2 (ja)
KR (1) KR20110081065A (ja)
CN (1) CN102116890B (ja)
TW (1) TW201134883A (ja)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8591644B2 (en) 2009-11-09 2013-11-26 Nitto Denko Corporation Liquid-crystalline coating fluid and polarizing film

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5623154B2 (ja) 2009-07-10 2014-11-12 日東電工株式会社 液晶性コーティング液および偏光膜
JP5942318B2 (ja) * 2012-02-28 2016-06-29 日東電工株式会社 偏光フィルム、画像表示装置、及び偏光フィルムの製造方法
CN106019453B (zh) * 2016-07-28 2018-06-15 京东方科技集团股份有限公司 组合物、复合偏光片及制作方法和显示基板
JPWO2021153374A1 (ja) * 2020-01-29 2021-08-05

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6277966B2 (en) * 1999-12-24 2001-08-21 Sumitomochemical Company, Ltd. Azo-compounds and dye polarizing films containing them
US7282574B1 (en) * 2006-02-10 2007-10-16 Everlight Usa, Inc. Dichroic azo dyestuff and the polarizing film making from the same
US7304147B2 (en) * 2003-04-16 2007-12-04 Nippon Kayaku Kabushiki Kaisha Azo compound and salt thereof
JP2008133421A (ja) 2006-05-30 2008-06-12 Mitsubishi Chemicals Corp 異方性色素膜用アゾ色素
US7445822B2 (en) * 2004-11-24 2008-11-04 Nippon Kayaku Kabushiki Kaisha Azo compounds and dye-type polarizing films or plates containing the same
US7514129B2 (en) * 2004-02-04 2009-04-07 Nippon Kayaku Kabushiki Kaisha Azo compound and polarizing film and polarizing plate each containing the same
US7527862B2 (en) * 2003-10-14 2009-05-05 Mitsubishi Chemical Corporation Dyes for anisotropic dye films, dye compositions for anisotropic dye films, anisotropic dye films and polarizing elements

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW223098B (ja) * 1991-10-24 1994-05-01 Hoechst Ag
JP5374940B2 (ja) * 2007-07-09 2013-12-25 三菱化学株式会社 異方性膜用化合物
JP2009057551A (ja) * 2007-08-08 2009-03-19 Mitsubishi Chemicals Corp 異方性膜用アゾ化合物
JP2009132748A (ja) * 2007-11-28 2009-06-18 Mitsubishi Chemicals Corp 異方性色素膜用アゾ色素
CN101861364A (zh) * 2007-11-28 2010-10-13 三菱化学株式会社 各向异性膜用偶氮化合物
JP2009155383A (ja) * 2007-12-25 2009-07-16 Mitsubishi Chemicals Corp 異方性色素膜用モノアゾ色素
JP2009294566A (ja) * 2008-06-09 2009-12-17 Nitto Denko Corp 偏光膜

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6277966B2 (en) * 1999-12-24 2001-08-21 Sumitomochemical Company, Ltd. Azo-compounds and dye polarizing films containing them
US7304147B2 (en) * 2003-04-16 2007-12-04 Nippon Kayaku Kabushiki Kaisha Azo compound and salt thereof
US7527862B2 (en) * 2003-10-14 2009-05-05 Mitsubishi Chemical Corporation Dyes for anisotropic dye films, dye compositions for anisotropic dye films, anisotropic dye films and polarizing elements
US7514129B2 (en) * 2004-02-04 2009-04-07 Nippon Kayaku Kabushiki Kaisha Azo compound and polarizing film and polarizing plate each containing the same
US7445822B2 (en) * 2004-11-24 2008-11-04 Nippon Kayaku Kabushiki Kaisha Azo compounds and dye-type polarizing films or plates containing the same
US7282574B1 (en) * 2006-02-10 2007-10-16 Everlight Usa, Inc. Dichroic azo dyestuff and the polarizing film making from the same
JP2008133421A (ja) 2006-05-30 2008-06-12 Mitsubishi Chemicals Corp 異方性色素膜用アゾ色素

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8591644B2 (en) 2009-11-09 2013-11-26 Nitto Denko Corporation Liquid-crystalline coating fluid and polarizing film

Also Published As

Publication number Publication date
JP5351060B2 (ja) 2013-11-27
CN102116890B (zh) 2013-06-05
JP2011141331A (ja) 2011-07-21
US20110163268A1 (en) 2011-07-07
TW201134883A (en) 2011-10-16
CN102116890A (zh) 2011-07-06
KR20110081065A (ko) 2011-07-13

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